A fixed bed catalytic reactor to be used for a gas phase catalytic reaction of an olefin or tertiary butanol to produce the corresponding unsaturated aldehyde and/or unsaturated carboxylic acid, or for a gas phase catalytic reaction of an unsaturated aldehyde to produce the corresponding unsaturated carboxylic acid, has a merit in that usually the flow of the reaction gas can be substantially approximated to the extrusion flow, and thus, the reaction yield is high, and an intermediate product in a sequential reaction can be obtained in good yield. On the other hand, the heat conduction ability of the fixed bed is low, and no adequate removal or supply of heat of reaction may be carried out, whereby the temperature within the catalyst layer may tend to be non-uniform, and in a highly exothermic reaction like an oxidation reaction, a temperature peak may be created within the layer so that the temperature control may become difficult, thus leading to a danger of a runaway reaction.
Further, in order to obtain the desired product in good yield, it is necessary to make the particle size of the solid catalyst as far as possible to reduce the dispersion resistance within the particles. On the other hand, if the particle size is made too small, the pressure loss will increase, thus increasing a possibility of a runaway reaction, and if the desired product is an intermediate product, the sequential reaction tends to proceed too much, such being undesirable.
In order to avoid the runaway reaction due to the temperature peak or to reduce the pressure loss, various methods have been proposed. For example, there are proposals such that when acrolein or the like is produced by a gas phase catalytic reaction of propylene or the like with air or gas containing free oxygen, the catalyst is shaped into a cylindrical form but not a circular column shape, whereby the pressure loss can be suppressed, and further, heat removing effect can be increased (see Patent Documents 1 to 3).
Heretofore, there has been known such a rotary powder compression molding machine for producing tablets, electronic parts etc. in which dies and upper and lower punches fitted to a rotary table are passed between upper and lower rollers with the rotation of the rotary table to move the upper and lower punches in their axial directions whereby powder filled in each die is compressively molded. In this type of rotary powder compression molding machine, there is of such a structure that in order to form a so-called cylindrical tablet being a ring-shaped product having a penetration hole in its center, a core punch is provided so as to project from the center of the punch end of a lower punch, and an upper punch has a center hole at the center of its punch end so as to allow the insertion of the core punch (see Patent document 4).
Patent Document 1: JP-A-59-46132
Patent Document 2: JP-B-62-36739
Patent Document 3: JP-B-62-36740
Patent Document 4: JP-A-10-29097